Influence of the Physicomechanical Properties of Starches on Their Tabletability—A Multivariate Analysis

Purpose The goal of this study was to identify correlations between the physicomechanical properties of different grades of starches with their tabletability. Methods Corn-starch grades (PURE-DENT® B700, PURE-DENT® B810, and PURE-DENT® B830) and pregelatinized corn-starch grades (SPRESS® B818, SPRESS® B820, and SPRESS® B825) were studied for physicomechanical properties, dynamic sorption isotherm, moisture content [MC] (% w/w), dehydration enthalpy (J/g) [ΔHd], and percent crystallinity (%). Tablets (6 mm) were compressed from hand-weighed powders (constant true volume) using Gamlen Tablet Press (Compression pressure-100 MPa; Compression speed- 5mm/s, 50 mm/s). Tablet mechanical strength (TMS) and Heckel parameters were evaluated. Correlation between physicomechanical properties and compression descriptors was evaluated by multivariate method. Results All starches followed Type-III sorption isotherm with open hysteresis loop indicating their large amorphous content. High amorphous content was further confirmed with hollow diffraction peaks of starches in the powder X-ray diffraction studies. Glass transition temperature of all starches was about 101°C. The moisture content and percent crystallinity of all starches was found statistically insignificant. However, PURE-DENT® B830 and SPRESS® B818 showed significantly low ΔHd values. Principle component analysis (PCA) loadings plot calculated with measured physicomechanical properties and TMS showed positive correlation between high Heckel Yield pressure values of plastic and elastic deformation and negative correlation with percent crystallinity, ΔHd, and MC along PC1. These relationships confirmed expected phenomenon in PCA score plots that Starches (PURE-DENT® B830 and SPRESS® B818) with plastic deformation followed by low elastic recovery in the decompression phase shows better tabletability. Furthermore, positive correlation of low ΔHd with TMS might indicate that starches with easy availability of associated water (low ΔHd) might have better tabletability due to water induced material plasticization. Conclusion Out of the six different grades of starches studied PURE-DENT® B830 and SPRESS® B818 showed better tabletability regardless of similar MC and amorphous nature. The better tabletability of these two starches might be attributed to their better plasticization due to loosely bound associated water, and low elastic recovery in the decompression phase